Embedded nonvolatile memory (NVM) devices include programmable cells which are widely used in electronic products for a variety of operations, including but not limited, to post fabrication testing and programming operations. An OTP cell can be programmed to store a bit using a fuse or an anti-fuse. The OTP cell generally includes a program gate and a transistor having a word line gate between source/drain regions. The program gate is disposed adjacent one of the source/drain regions, and a bit line is coupled to the other of the source drain regions. The word line gate serves as the word line for selecting the OTP cell. When a normal voltage is applied to the word line gate, the equivalent circuit for the transistor is a capacitor and appreciable current (current indicative of a first storage state) does not flow to the bit line. When a program voltage is applied to the program gate, a thin dielectric portion of the program gate breaks down and a resistive path from the channel of the transistor to the program gate is created. The equivalent circuit for the transistor is a resistor after the program voltage is applied and appreciable current flows to the bit line when a normal voltage is applied to the word line gate and the program gate.
OTP cells are generally provided on bulk substrates using conventional complementary metal oxide on semiconductor (CMOS) technology. OTP cells are isolated from each other on the bulk substrate by shallow trench isolation structures which occupy space on the semiconductor substrate, thereby decreasing cell density.